1. Double-layer effects on low frequency dielectrophoresis-induced colloidal assembly.
- Author
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Hoffman, Peter D. and Yingxi Zhu
- Subjects
- *
DIELECTROPHORESIS , *COLLOIDS , *ELECTRODES , *NANOPARTICLES , *NANOSTRUCTURED materials , *ELECTRIC fields - Abstract
Strong frequency dependence of particle aggregation in applied ac-electric fields is reported for colloidal assembly under positive dielectrophoresis. A curious low-frequency threshold ωth on the order of 104–105 Hz is observed for the onset of collecting submicron latex particles at the high-field regions near coplanar electrodes. Similar to the dielectrophoretic crossover frequency, ωth is independent of medium conductivity, σm at low-salt concentration, yet scales with σm0.5 at high-salt concentrations. This intriguing salt effect suggests the distinct contribution from Stern and diffuse layer conductance to the interfacial polarization mechanism of latex particles in nonuniform ac fields. [ABSTRACT FROM AUTHOR]
- Published
- 2008
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